Basic evidence

Chunking by pigeons was demonstrated by comparing performance on different types of lists. Experiment 1 showed that Groups II and IV (who leanred lists in which colors and achromatic geometric forms were segregated: A B C D' E' and A B C D E', respectively) executed lists more rapidly than did Group I (who learned a homogeneous list of colors: A B C D E) OR Groups II and III (who learned lists consisting of unsegregated colors and forms: A B' C D' E and A B C' D E, respectively). Experiment 2 showed that Groups II and IV tolerated interruptions of the list better than did Groups I, III, and V. The accuracy of responding of Groups I, III, and V decreased as a function of the duration of the interruption and the point in the sequence at which it occurred. The performance of Group II was unaffected by interruptions; Group IV was minimally affected. These results indicate that Groups II and Iv organized their lists as ordered chunks.